The present invention relates to a communication method and a communications control apparatus adapted for circuit switching networks in which a user is charged with a relatively high communication fee, examples of such circuit switching networks being an automobile telephone network or a portable telephone network, wherein a user pays a charge in accordance with the connect time.
FIG. 1 is a diagram explaining the data communication using a conventional circuit switching network. Specifically, FIG. 1 shows the data flow observed from the user terminal when a personal computer communication is carried out via a modem having a built-in network control unit (NCU). In the figure, DTE indicates a terminal; CCU a communication control unit (or DCE: data circuit terminal equipment). CCU and the terminal of the personal computer communication host are connected to CCU and the terminal of the user via a communication network.
As shown in FIG. 1, when observed from the user side, the user remains connected to the circuit even when there is no communication data (no-data state), this being so until the user terminal issues a disconnection instruction or the circuit is disconnected from the user.
When the network disconnects the circuit from the user, it either turns off a carrier detection signal (CD) or transmits a character string "NO CARRIER" to the terminal so as to notify the terminal of the circuit disconnection.
Hence, there is a problem that, in circuit switching networks in which a user is charged with a relatively high communication fee such as an automobile telephone network or a portable telephone network, the circuit is used in a wasteful manner because the user is charged even when there is no data to be transmitted or received.